[Intel-gfx] [CI] drm/i915/selftests: Add tiled blits selftest

[Chris Wilson]

Quoting Chris Wilson (2020-04-30 07:49:57)
> From: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> 
> Extend coverage of the blitter client by exercising conversion to and
> from tiled sources. In the process we perform spot checks to verify that
> the tiling/detiling is being applied correctly, along with position
> invariance of the tiling parameters.
> 
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

This does what I asked for a minimal and accurate replacement of tiled
blits, thanks! It can be bumped for sensitivity (spot check a few more
pixels, or the whole surface), it can also be adjusted for checking
tiling parameters and fine copies. What it tests right now is that we
can move objects around inside the GTT without losing tiling, which is
the foundational level of assurance we need.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris